There are known various types of power stations utilising sea currents, river currents and tides by applying turbines placed in the water current. Utilisation of the energy in flowing sea or river water or in tides requires a power station which is arranged in such a manner that it will automatically adapt itself to the changing direction and speed of the water current and which will moreover operate satisfactorily even if there are great variations in the depth of water due to the tide and weather conditions in general. Furthermore, the station should be dependent on the depth of water so that it may find use within a depth range of 6 meters to 4 kilometers.
It is the object of the invention to provide such a floating power station affording a very substantial energy take-up and which will always adapt itself to the water flow and to the turn of the tide and which is designed in such a manner that it is particularly simple to maintain and repair.
This is achieved by designing the tidal power station according to the invention as disclosed. By inspection, repair work or replacement of one or more of the turbines, the entire turbine formation is pulled up into the water surface within the area limited by the ring pontoon where the waves are substantially calmed by the ring pontoon which for example obviates the need for awaiting calm weather before doing repair work. Furthermore, the ring pontoon surrounding all the turbines offers favourable working conditions so that it is not necessary to sail an auxiliary vessel or a barge crane out to the power station in order to be capable of commencing repair work or inspection.
Optimum utilisation of the ring pontoon is achieved by designing the power station according to the invention as disclosed in the dependent claims. It is possible to mount a great number of turbine units in the power station thereby providing a substantial power take-up and so running the station profitably. The shape of the ring pontoon means that the rear part may serve as a suspension for the turbine formation which is almost weightless in the water; the front part serves as a mooring part and the sides serve to be capable of supporting the swung up turbine formation during towing and servicing.
To ensure that the ring pontoon is correctly positioned in the water so that the propeller plane of the turbines is always at right angles to the direction of the water current the power station according to the invention is preferably designed as disclosed in the dependent claims. It is thus possible to have an anchor point far below the water level and all forces directly to the anchor point around which the entire power station may swing. The result is that the ring pontoon will not take a lopsided position in the water even by a very substantial energy take-up in a strong water current such as a tidal current between high and low tide. The power cable is carried down through the bitt from slip-ring contacts at the top. When connecting and disconnecting the wire assembly means, a wedge arrangement retaining the wire assembly means may be manoeuvred from inside the mooring bitt.
Additional stability towards powerful changes in current etc. is achieved by designing the power station according to the invention in the dependent claims. In this manner all tractive forces are transmitted to the anchor warp without problems and the power station will always rest quietly and stably with the ring pontoon planely in the water surface.
By designing the securing of the internal warps as disclosed in the dependent claims, a simple way of mooring the power station to the mooring bitt is obtained.
By designing the power station according to the invention as disclosed in the dependent claims, it is possible in a simple manner to place the entire turbine formation in a position permitting service and repair work to be done and back again in its operational position using quite simple means. It is possible to carry out all these operations from the power station without any help from auxiliary vessels, barge cranes etc. and without any significant change of the stability of the floating power station.
By designing the power station according to the invention as disclosed in the dependent claims, it is possible to achieve an arrangement of the turbines on the central beam which is correct relative to power and moment. Connection and disconnection of the turbines powerwise should take place in pairs but purely physical replacement of for example a damaged turbine may without problems take place separately.
Preferably the power station according to the invention is designed as disclosed in the dependent claims. It is thereby possible to locate all auxiliary equipment and service equipment on and inside the ring pontoon. It is possible to carry out any form of repair work or maintenance on site without any outside help. The inside of the ring pontoon serves as a housing and as a transport route for installations and equipment. The purpose of the crane is to lift and mount the internal ring assembly of the anchor warps over the mooring bitt and to service and replace the turbine units which are almost weightless in the water, and moreover to operate as lifting gear for spares and other appliances.